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How to Wake Up a Geriatric Squid

Poking it a little helps.

Hawaiian bobtail squid are nocturnal, and glow in the dark.
Hawaiian bobtail squid are nocturnal, and glow in the dark. Plos Biology/CC BY-SA 4.0

Brightly colored Hawaiian bobtail squid live in the shallow coastal waters around Hawaii. Maxing out at about the size of a small lime, these spotted invertebrates are notable not just for being wholly adorable, but for the curious relationship they have with the bioluminescent bacterium Vibrio fischeri. V. fischeri live in the squid’s light organ, and let off a furious glow. In the dark, the nocturnal squid use their light organs to help them camouflage—pretending to be moonlight.

At the University of Connecticut, scientists are studying how the squids’ immune cells recognize these good bacteria from the thousands of species of other microbes floating around in the seawater. It’s intricate work—lots of squinting through microscopes—and often requires using samples of blood, drawn from the squid who live in the lab. And for that, scientist Sarah McAnulty explains, the squids must be anesthetized for a minute or two. “It’s way less stressful for the animal to be knocked out,” she says.

To put a squid to sleep, you simply pop them in a seawater solution of three percent ethanol. Once you’ve taken their blood, they need to be woken up again. Under anesthetic, blood doesn’t pump quite as well around their systems, so to get them going, first McAnulty will use a pipette to blow fresh seawater over their gills. This kickstarts their normal breathing, and begins to get their blood pumping once again, she says. “It’s sort of like the squid version of CPR—but they’re so squishy I don’t want to hurt them by compressing their hearts.”

SJM530a, who appears in this video, is a very old squid. At five months old, this male squid, who was raised in a laboratory, is practically geriatric—so waking him up after he’s been anesthetized takes a little bit longer. She’ll give them a moment or two to breathe at their normal rate, then start tapping them with a pipette. “They wake up faster when you tap them,” she says. Normally, it’s two taps and presto! They’re up. But SJM530a’s old age means that he requires a bit more prodding.

In the lab, these squid seldom live longer than about five months; in the wild, they might make it to nine or 10 months. Because there are so many squid in the lab, they rarely get more romantic names than arcane strings of numbers and letters—unless, of course, they do something to endear themselves to the scientists. “If they do something really silly,” McAnulty says, “we might give them a nickname.” While SJM530a may not have gotten a nickname in the lab, we in the newsroom think he looks a lot like a “Flappy.”